Underfeed domestic stoker



FEE. 3.

1948. J. c. scoTT 2,446,492

UNDERFEED DOMESTIC STOKER Filed April 22, 1941 5 Sheets-Sheet 1 INVENTOR.

Jul-1n 5131:1111.

Aug. 3, 1948. SCOTT 2,446,492

UNDERFEED DOMES TI C S TOKER Filed April 22, 1941 5 Sheets-Sheet 2 FIG. 2. 3

ATTORNEYS.

Aug. 3, 1948. J. c. soon I 1 2,446,492

UNDERFEED DOMES TI C S TOKER Filed April 22, 1941 5 Sheets-Sheet 3 I I I I I I 1 I I II II [III III John ll. 51:01:11

ATTORNEYS.

Aug. 3, 1948. J c -r 2,446,492

UNDERFEED DOMESTIC STOKER a; Filed April 22, 1941 5 Sheets-Sheet 4 INVENTOR.

2 John E Ecpfi.

ATTORNEYS;

Aug. 3, 1948. J. c. scoTT UNDERFEED DOMESTIC STOKER 5 Sheets-Sheet 5 Filed April 22, 1941 FIG. 7.

FIG. 6.

INVENTOR. J :fiu-L E. E c. 0111 Patented Aug. 3, 1948 UNDERFEEI DOMESTIC STOKERv John. e. Scott, Beckley, W. Va., assignor toThe New .RiverCompany, Mount Hope, W. Va a,

corporation Application April 22, 1941; Serial No. 389,803

This invention relatesto derfeed domestic S'bOkQlS'r The primary object of thisyinventionyis the rovision --of a stoker of. the :underfeed-type, which canvbe compactly assemblem. andin- Which-the dimensions of partsbetweenthepower unit and burner are standardized.-

- In conventional bin-feed type of stokerslit has been usual to: (a) placethespower unit at-the coal bin: and. drive theconveyor screw by a shaft extending into thelcoal; (b) .placatherpower unit on=theopposite side of.v the boiler or furnace from theicoal tube, or (c) -use.a complicated transfer systeminwhich coaleispulledv into the feed box by one ,screw and thencarriedinto the burner by: another.- These 7 methods Y are mainly obimprovements unjectionable -becausethey requirev expensive installation-costs and. are; not I compactly arranged.

Floor space adjacent the burner is usually limited, so that :its conservation is desirable.

With my improvedunderfeed :domestic stoker, the dimensions between the power unit; and burnerarestandardiZedand;-parts are so arranged as to conserve floor space, ancLthejinstallation', costs are less,than with'any. of the abovementioned conventional installations. Furthermore. my. arrangement enables a the conveyor or feed screwfrom the. power unit to the bin to beadjusted inlength tosuit conditions, with comparative ease.

Inthe drawings, wherein for the purposeiof illustration-is shown only a preferred embodiment of the invention, v

Figure 1 is a side elevation of the improved underfeed-stoker. a

Figure-2 is across sectional view takenthrough the drive gearingmechanism; substantially on the. line 2-2 of Figure- 3;

- Figure 3 isv a vertical sectionalrview taken through the motor. and reduction gearing; of the conveyor screw; substantially on.the 1ine-:3-.-3:of Figure ,2. i

Figure 4. is a detail of a section of the conveyor screw.

Figurev 5 is a fragmentary vertical sectional view taken through the burner head: or fire box,

showing the horizontal and verticab feed. screw arrangements associated therewith.

Figure 6, is; a fragmentary sectional view showing the manner in which an; extension. section of the conveyor screw and; feed housing is supported.

Figure 7 is a vertical sectional view takensubstantially on the line l-lof Figure ,6.

In the drawings, whereinsimilar reference characters designate corresponding parts Claims. (01. 1104- 45) throughout the. several views, the letter A; may generally designate, the improvedunderfeed domesticstoker. It includes a .burner head. or fire box B; horizontal feed sc rew construction 0-; motor. .D; speed reduction-gearing E for .thedrive of the horizontal fecd screw construction C blow.- er fan F; air regulation and control .meansG, and a verticalieed screwnconstruction H. I

The. power plant portion of the. improved stoker A p referably, includes a supportingcasing having openingszl therein through which the feed screw-construction C-.extends The portion of the -feed;screw construction C which. 'ex tends through openingsll consistsoi a coreless screwbody23. shown best in Figure 4 of the drawings, having a plurality of. spiral convolutions and at the ends thereoi being. providedwith axial malesand female. extensions 24 and 25 adapted to. bev detachablyconnected with the shaft. portions of the adjacent conveyor screw, sectionsv 26 and,2'|. The. conveyor. screw section. 26 is of standardized length and positioned between the power unit and the burnepheadB, The other screw section 21 maybe. 01 any. desired length and usually is constructed of l a. plurality of.- sections to suit the distance from the power plant or ,unit to thewcoal binor. storage compartment. Both of these .section s.26. and.v 21 .areprovided with axial shafts. and have spiral .convolntions thereon, as shown in the drawings.

Referring again to the corelessscrew section 23 thesame is provided with arelativelythin ring shaped portion 30 integrally connected'ataperipheral edge: of the central convoluted portion.

The-disc is provided with transverse bolt. receiving openings 3 l therein; 7 l

The coreless. screw section 23. is. assembled g in' the casing 20. upon stationary sleeve. portions. and 36., .The .latterhave pressed litsfin the openings 2| .of the casing 2i). as "best. shown inFigure 2 or the drawings the adjacent ends of the sleeves 35 and 35 being pressed at their edges againstthe' ring shaped portion 30 of the section 23, as shown in Figure v2 of the drawings. It is to be noted'that the thicknesses of adjacent ends ofthe sleeve are reduced, so as to provide an oil tight fit. The internal diameter of'the sleeves 35 an'd'36 is'the same as the opening through the disc30; the edges of the spiral convolutions having a sliding fit within-the sleeve portions 35' and 36, as shown in Figure 2 of thedrawings.

Referring in detail tothe drive gearing E, the disc portion 30 of the conveyor shaft section '23 has arin'g shaped gear =bolted thereto as at-5I. These bolts-5:1 also seoure hub extensions 53 and 'of the air casing leading to the fire box.

54 to opposite sides of the web of the gear 50; the said hubs having bronze bearing sleeves 56 and 51 pressed therein so as to rotate therewith. The bearing sleeves 56 and 51 receive the major lengths of the conveyor screwsupporting sleeves 35 and 36 therein and receive: the thrust of the conveyorscrew section 23. Suitableoil ducts 60 may lead from the gear box compartment 20a between the bearings 565'I and the outer surfaces of the stationar supporting sleeves 35-36, as shown in Figure 2.

Referring at this time to other details of the power plant, the motor D is mounted by a spring supported platform 10 upon thetop ofthe casing 20. It has a shaft extension II at one end provided with a drive pulley 12. A belt I3 is trained thereupon and also upon another pulley 14 of the drive gearing. The other end of the motor shaft, designated at I6 has a blower fan F keyed therewith.

The pulleys 12-14 and their belt I3 are located in a suitable'auxiliary housing I8, and the pulley I4 is keyed upon a worm 80 rotatably mounted in bearings 8i and 82 at the top of the gear casing 20, as shown in Figure 3. These bearings are kept lubricated from oil'tro ghs 83.

The speed reduction aand drive gearing E preferably includes a worm gear 85 meshing with the worm 80 and keyed upon a shaft 86. The latter also has a pinion 81 keyed thereon and meshing with a larger gear 90. The latter is keyed upon a counter shaft 9|. A pinion 92 is keyed upon shaft 9i and meshes with the gear 50 above described as being keyed with the conveyor screw section 23. mounted in bearings upon the gear box 20', shown in Figure 2 of the drawings.

Referring to thefire box construction 28, the same includes a casing I having the conventionaltuyres assemblage I III therein, arranged so 'as to permit the air supplied by the fan to mix with the coal as the latter is forced into the fire box compartment I02.

The conveyor screw section 25, as before mentioned, is drive connected with the section 23, as shown in Figure 2 of the drawings, and is housed at I03. The tubular housing I03 opens into the lower portion of the fire box compartment I02, and

the coal is conveyed from the'section 23 via the section 26 to the fire box compartment.

bearings III in the gear casing 20 and having a pinion l I 2 keyed therewith meshing with the gear 3'. The latter has a keyed fit upon the hub sleeve 54 of the gear 50 above described, and as shown in Figure 2 0f the drawings. The shaft I I0 is located immediately below the conveyor feed screw, and is suitably housed in a portion H The horizontal shaft H0 is divided into several sections which are connected by flexible couplings ll'l so as to. permit of the accurate mounting of theshaft section adjacent to the fire box. This shaft section ismountedin suitable bearings I20.

The vertical feed screw I25 has a vertical shaft section I26 mounted in suit-able bearings I21 in, the fire box casing assemblage and is provided with a bevel gear I29 meshing with a bevel gear I28 keyed to the end of the'shaft H0. The feed screw portion I25 directly faces the terminal end of the horizontal conveyor screw section 25 and Both of the shafts 86 and M are similarly 0 Various changes feeds the coal upwardly into the fire box compartment I02 to the desired height. The provision of this vertical feed screw eliminates crushing of the coal at the bottom of the retort and enables the finer coal to be uniformly admixed with the other aggregate, so that an even burning of the coal in the fire box is assured.

In connection with the introduction of forced air, the blower assemblage includes a fan F housed within compartment of easing I50, the compartment of the casing outlets thru a, vertical duct I5I into a box or casing H5. The latter is open to the compartment wherein the conveyor screw section 26 is disposed. Clearances between this screw section and the housing I03 within which it rotates, as will be noted from Figures 2 and 5 of the drawings, permit the air under forced pressure to enter the fire box at the location of the vertical feed screw construction H. It will be noted that within the duct I5I there is disposed a damper control construction which may consist of any conventional thermostatically controlled damper arrangement.

The conveyor screws 21 are housed in suitable feed tubes 220, and a number of these maybe provided, since the length from the power plant to the coal storage location may vary. To that end the tube section 220 may be enlarged at 22! to receive the ends of an adjacent section 220, as shown in Figure 6 oi. the drawings. The tube sections 220 are provided with supports consisting of sleeves 223 mounted for vertical adjustment upon suitable standards 224 and held in proper adjustment by'mea'ns of set screws 225. Suitableclamping screws 22'! hold the tubes 220 in position. If desired, inspection segments 230 may-be placed in certain parts of the tubes 220, for the purpose of inspecting the conveyor screws, etc i in the shape, size and arrangement of parts may be made to the form herein shown and described, without departing from the spirit of the invention or the scope of the claims.

I claim: 7

1. In a stoker, the combination of a conveyor tube, a rotary screw mounted for rotation in said tube, said screw comprising endsections each having shaft portions and spiral convolutions thereon, and an intermediate section provided with coreless convolutions, said intermediate section at the ends thereof having stub shaft portions for connection with the shafts of the other sections, and a driving gear connected with the intermediate screw section.

2. As an article of manufacture, a conveyor screw section for stokers comprising coreless spiral convolutions having end stub shaft portions, and means for connecting a driving gear to the outer periphery of the coreless spiral portion of said conveyor screw at a location between the stub shaft portions.

3. In a stoker, the combination of relatively spaced rotary conveyor screw sections, a drive gearing casing, an intermediate conveyor screw section comprising a plurality of coreless spiral convolutions having end stub extensions detachably connected with the above mentioned spaced conveyor screw sections, a drive gear peripherally connected with the intermediate conveyor screw section, stationary sleeve sections upon the gear casing at each'side of the drive gear, bearing means connected with the drive gear and externally bearing upon said'sleeve sections, and means for driving the drive gear.

4. In a drive mechanis'mfor conveyor feed sesam screwsf the combination of--"end-wise spaced co veyor fed screws; tubularfeed hbusings thfere for? airintermediate-coreless spiral conveyor with means to key-thesame to tlfe conveyor screw sections first mention-ed, a=-drive-gear havingpe ripli'eral connect-ion" upon the core'less s'pirar of tlfeintermediateconveyor*"serew "section; tubuiar staft'ionary sieresections-receiving the intermediate screW-sectionin ratherc'losefitting coiita'ct therein at-each side of'said drive gear, and bear ing meansupon-said*sleeve-sections for tlie'drive gear. .:,g A: v

5. As an article of manufacture, a conveyor sorew"'s'ection for stokerscomprising a..co'reie'ss spiral *convolutedportioir'having intermediate its ends a. peripherally attached ring-shaped drive attaching member the thickness of which at the passageway thereof which is exposed to assage of fuel therethru, is less than one-half of the overall diametrical dimension of the screw.

6. As an article of manufacture, a conveyor screw for stokers and the like comprising a coreless screw section, end axle stubs attached at the ends of the coreless screw portion, and a ringshaped attaching disc disposed in a plane normal to the axis of the coreless screw section said ring having a passageway therethru of the same diameter as the overall diameter of the coreless screw section at the location of said ring, and the peripheral portion of the coreless screw section at the location where it extends thru the said ring being fixed with respect to the ring in the passageway of the-ring.

7. In a stoker, the combination of a conveyor tube, and a continuous spiral screw rotatably mounted in the tube comprising end sections having spiral convolutions and axial shaft portions, an intermediate coreless screw section having spiral convolutions continuous with the spiral convolutions of the end sections, means detachably keying the ends of the coreless screw section to the axial shaft portions of the end sections, and means connected peripherally with the coreless screw section for driving the same and the end screw sections.

8. As an article of manufacture, a conveyor screw section for stokers and the like comprising coreless spiral convolutions having peripherally connected intermediate the ends thereof a ringshaped drive attaching disc.

9. As an article of manufacture, a conveyor screw section for stokers and the like comprising coreless spiral convolutions having peripherally connected intermediate the ends thereof an outwardly disposed ring-shaped drive attaching disc, and conveyor attaching means at the ends of the coreless screw convolutions.

10. In a stoker conveyor the combination of spaced axially aligned rotary conveyor screw sections, conveyor tubes in which said rotary screw sections rotate, an intermediate coreless screw section of spiral convoluted form having end connections with the aforesaid screw sections, stationary conveyor screw supporting sleeves in closely spaced relation supporting the ends of said coreless screw section, a relatively thin annular member rigidly connected peripherally with the coreless screw section intermediate the ends of the latter and extending in relatively close fitting relation circumferentially in the space between the ends of said sleeve sections, a gear connected with said member externally of the sleeves for drivifig said core less screw sectione and bearringF means orr'said jsleves su-pporting saidkigearr Hi new stoker 'conveyor the combination of spaced axially aligned rotaryconveyor screw sections, conveyor tubes iii' wh'ich said' rotary screw relation circumferentialiy. in the space between assesses: ofusaidsleevesections; aige'ar connected saidtm'ember. externallyrof the slevessfdr driving; 'sa id corelessscrew rs'ect-ioirg andii beariih'g means on said sleeves supporting said gear consisting of soft metal bearing sleeves connected with said gear and rotatably bearing directly externally upon said sleeves.

12. As an article of manufacture, a conveyor screw for stokers and the like comprising a coreless screw section, a ring-shaped attaching disc disposed in a plane normal to the axis of the coreless screw section, said ring having a passageway therethru of substantially th ame diameter as the overall diameter of the coreless screw section at the location of said ring, and the peripheral portion of the coreless screw section at the location where it extends through said ring being fixed with respect to the ring and in the passageway of said ring.

13. In a stoker, the combination of a burner box, drive gearing, a horizontally disposed conveyor screw assemblage connecting the drive gearing with the burner box, including an intermediately disposed conveyor screw section to which said drive gearing is directly attached, a vertical lift screw for the burner box at the end of the horizontally disposed conveyor screw assemblage, a horizontally disposed shaft below the horizontal screw assemblage having connection at one end with said drive gearing at the intermediate section of said horizontally disposed screw assemblage and at its opposite end having a drive connection with the vertical lift screw.

14. In a stoker, the combination of a conveyor tube, a continuous spiral screw rotatably mounted in the tube comprising end sections and an intermediate coreless screw section continuous with the said end sections, conveyor driving means connected peripherally with the coreless screw section shaped to pack the coal at said coreless screw section just sufiicient to prevent back passage of free draft along said conveyor tube, a burner at an end of said continuous spiral screw, and means for forcing a draft into the tube and along the continuous spiral screw at a location between said intermediate coreless screw section where the coal packs and said burner.

15. In a stoker construction the combination of a coal conveyor tube, and a continuous spiral conveyor screw mounted therein comprising end sections each having axial core portions and spiral convolutions thereabout, an intermediate coreless screw section comprising a, plurality of screw convolutions each extending thru at least 360, means detachably keying the ends of the coreless screw section to the adjacent ends of the end sections so as to provide a continuous extension of the screw convolutions of the end and intermediate sections of the spiral screw, and means connected 7'. with the coreless screw section intermediate the Number V ends thereof for driving said spiral screw. 2,064,283

1 3 JOHN C. SCO'I'I'. 2,073,059 2,103,145 REFERENCES CITED 5 2,122,050 The following references are of record in the file of this patent. 2:165627 UNITED STATES PATENTS 2,170,277 Number Name Date 1 2,191,219 1,032,350 Mount July 16, 1912 2,210,329 1,541,648 Martin June 9, 1925 2,224,991 1,560,203 Carey Nov. 3, 1925 4 1,560,204 Carey Nov. 3, 1925 1,729,776 Hare Oct. 1, 1929 15 7 1,379,342 Lauter Sept. 27, 1932 Number 2,034,390 Wynn, Jr Mar. 24, 1936 47,053 2,122,708

Banfield July 5, 1938 Name Date Wright Dec. 15, 1936 Guthrie Mar. 9, 1937 7 Carter Dec. 21, 1937 Stuart June 28, 1938-, Marsh Mar. 7, 1939 Schwabach Apr. 4, 1939, Fricchione July 11, 1939- Richardson Aug. 22, 1939 Peltz Feb. 20, 1940 Schweizer Aug. 6, 1940 Schweickart et a Dec. 17, 1940 Casey Jan. 14, 1941 FOREIGN PATENTS Country Date Sweden Dec. 24, 1913 

